The present invention relates to the construction of an optical connector for connecting two optic cables to each other.
Since an optic conductor with a transmission loss of 20 dB/km was developed, the optic conductor has been remarkably advanced not only in the field of communications but also in the various fields of its application such as measurements, information processing, energy transmission etc. Optical cable is comprised of a light transmitting fibers made chiefly of quartz, which are not only far superior to any conventional metal transmitting circuit in the quality of the information transmitted but are also able to provide many advantages such as high tensile strength, high flexibility, easy maintenance and simplicity of application. Furthermore, there are abundant materials available for making optical fibers. All the above-mentioned advantages will facilitate the further development of further applications. A typical optical fiber comprises a quartz core of 100 to 150 .mu.m in diameter surrounded by a clad chiefly made of quartz, a reflective index which is less than those of the core and more than that of air.
Since the tensile strength of the clad is extremely affected by any mechanical damage, its surface is protected with a urethane or some other polymer film covering of about 10 .mu.m in thickness and is further covered with an outer covering of nylon resin or the like. The optical fiber thus formed is called an optical fiber core. Each core has an outer diameter of about 0.9 mm and is reinforced with a material for increasing tensile strength as well as another outer covering of about 3 mm in diameter. The above-mentioned optical fibers are available as spacer-cables for use in multiplex communications, underground cables etc.
In the case of cables the chief problem is to secure a correct connection of the fiber optic cables. Usually, in practice, a cable-splicing method is adopted for permanently connecting the optical fibers but it is inadequate in cases where a fiber optic cable is used between transmitting and receiving devices or is connected to any component of fiber optics such as light switches, light couplers etc.
In such cases an optical connector for connecting the fiber optic cables must be used. The requirements for connecting mishaps by the optical connector are not as serious as compared with those in splicing since the connector is seldom used on communication lines. It is basically important that the optical connector have high reliability in connecting and mechanical strength since it is frequently used for connecting and disconnecting. More specifically, it is necessary to make the connector compact, easy-to-use and suitable for mass production.
In view of the foregoing, two types of optical fiber connectors, namely, adjustable and non-adjustable ones, have been developed. The former is a connector which can be adjusted so as to minimize the connection loss, for instance, by turning an eccentric sleeve to align the optical fiber ends to each other. Such an adjustment is performed by monitoring the light transmission through the fibers until the maximum value is obtained.
The latter is a connector, wherein optical fiber ends are guided by a metal cylinder of an accurate diameter so as to mechanically align them to each other.
Concerning the connection of optical fiber, as for example for use in communications, many and various kinds of optical connectors were developed and used in the past. However, optical connectors for connecting fiber optic cables having a quantity of optical fibers for light-energy transmission, due to small demand for them, had hardly been proposed. Of course, the above-mentioned optical connectors for communications could be used for such a purpose but they had to be precisely finished for assuring an accurate alignment and connection of quantities of very fine optic fibers. The cost could be prohibitive.
The applicant previously proposed that solar rays be collected by a lens system, introduced into a fiber optic cable and transmitted anywhere they were needed as for illumination, solar bathing or for other various purposes.
In each case, the solar rays transmitted via optical fibers could be most effectively utilized if various kinds of terminal devices could be selectively used, according to the different applications, by removably connecting the fiber optic cable ends to them. In the past, optical connectors for doing the above were not provided.